Centrifuge

ABSTRACT

A centrifuge for serum/plasma separator tubes in which racks holding one or more tubes can be inserted into slots in the rotatable member of the centrifuge. The slots of the rotatable member are positioned to provide dynamic balancing when all the slots are filled with racks of tubes. When the slots are not all filled with racks of tubes, the centrifuge is so designed that such racks can be positioned opposite each other to maintain such balance. In a modified form, the entire rotatable member loaded with racks of tubes can be loaded onto or removed from the centrifuge as a unit, thereby providing a quick, convenient and simple way of handling a full load of tubes at one time.

United States Patent 11 1 14 1 June 24, 1975 Ayres CENTRIFUGE [75]Inventor: Waldemar A. Ayres, Rutherford [73] Assignee: Becton, Dickinsonand Company,

East Rutherford, NJ

[22] Filed: Feb. 27. I974 [2i] Appl. No: 446,369

[52] US. Cl. 233/26 ]5 I] Int. Cl. B04B 5/00 [58] Field of Search 233/!R, 26, 27 28 I56] References Cited UNITED STATES PATENTS 330179 I H1885Frcderiksen ct alv 233/26 486390 1 H1892 Berg 1 w 1 1 1 1 c 11 233/262.560.988 7/l95l Ruda 1 l 233/26 2.893.458 7/l959 Flora 1 i l6/l2l X3.050139 8/1962 Williams .1 233/26 X Primary E.taminerGeorge H.Krizmanich Attorney. Agent. or Firm-Kane, Dalsimer. Kane, Sullivan andKurucz [57] ABSTRACT A centrifuge for serum/plasma separator tubes inwhich racks holding one or more tubes can be inserted into slots in therotatable member of the centrifuge. The slots of the rotatable memberare positioned to provide dynamic balancing when all the slots arefilled with racks of tubes. When the slots are not all filled with racksof tubes, the centrifuge is so designed that such racks can positionedopposite each other to maintain such balance. In a modified form. theentire rotatable member loaded with racks of tubes can be loaded onto orremoved from the centrifuge as a unit. thereby providing a quick.convenient and simple way of handling a full load of tubes at one time.

7 Claims, 9 Drawing Figures PATENTEDJUN24 ms 3891 I140 SHEEY I l' N l "Ii lOb 13,891II4U PATENTEUJuu 24 I975 SHEET PATENTEDJuu 24 ms SHEET lOuPATENTED Jun 24 ms FIG. 9

SHEET CENTRIFL'GE BACKGROUND OF THE INVENTION The prior art includes thefollowing pertinent US. Pat. Nos.

None of these patents show or describe a centrifuge head embodying themeans. hereinafter described and claimed. for mounting a plurality ofracks holding a plurality of separator tubes on the periphery of thehead and for holding such racks on the head during rotation of the head.Furthermore. such patents do not disclose the specific design of theracks for holding the plurality of tubes.

SUMMARY OF THE INVENTION It is an object of the present invention toprovide a centrifuge for separator tubes designed to hold a plurality ofracks or tubes on the periphery of a rotatable member. which racks canbe positioned on the said member to maintain dynamic balance duringrotation of the centrifuge.

It is a further object to provide racks for the centrifuge which willhold a plurality of tubes and are so designed that they can be fittedinto support means on the periphery of the rotatable member of thecentrifuge.

It is a further object to provide means on the centrifuge for holdingthe racks and tubes so that they cannot leave the support means duringcentrifugation.

It is a further object to provide a centrifuge with a removablerotatable member which will hold racks of tubes so that all the racksand tubes supported on the rotatable member can be removed as a unit tofacilitate loading and unloading of the centrifuge.

BRIEF DESCRIPTION OF THE DRAWINGS Other objects and advantages willbecome apparent from the following description which is to be taken inconjunction with the accompanying drawings, in which:

FIG. 1 is a perspective view. partly broken away. of the centrifuge ofthe present invention;

FIG. 2 is a side elevation. partly in section. showing the centrifugewith one rack of tubes in place on one side and the rack on the oppositeside removed;

FIG. 3 is a top plan view of a portion of the centrifuge showing how theracks of tubes are inserted downwardly into the top of the centrifuge.

FIG. 4 is a perspective view of the rack of tubes which is inserted intothe centrifuge;

FIG. 5 is a side elevation. partly in section. of the tube rackcontaining sis tubes;

FIG. 6 is a view. partly in section. along the line 66 of FIG. 5;

FIG. 7 is a top plan view of the tube rack.

FIG. 8 is a perspective view. partly broken away. of a carrier forholding a plurality of tube racks: and

FIG. 9 is a perspective view of a modified form of centrifuge in whichthe entire rotatable member holding the tube racks can be removed as aunit.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to FIGS. 4-7.serum/plasma separator tubes I0. provided with top and bottom stoppers10a and 10h respectively. are shown resting in a rack II. This rack maybe formed of a strong non-corrodable material. for example stainlesssteel. It consists of a bottom I2. side members l3-I3 and flanges l4-[4. The opposite side members 13 are spaced to provide adequateclearance for the tubes. The rack. as shown. is of a size to hold sixtubes. but it will be understood that such size may be varied to holdmore or fewer tubes. A flat plate 15, preferably also made of stainlesssteel. extends across the top surfaces of the flanges I4 and is rigidlysecured to them by any suitable means. for example by welding. The topplate 15 is provided with a plurality of holes 16 to receive the tubesI0 and keep them uniformly spaced from each other. These holes are of asize that they will provide sufficient clearance to receive the lowerstoppers of the tubes I0. Secured to the bottom I2 of the rack is aspacer guide 17 having a plurality of holes I8 corresponding in numberto the holes I6 in the top plate 15. The holes I6 and 18 are aligned sothat the tubes inserted into the top plate 15 and the spacer guide I7will keep the tubes parallel and uniformly spaced.

Referring to FIG. 2, there is a motor housing I9 from which extends themotor shaft 20. The motor enclosed within the housing is of aconventional type for driving a centrifuge and is not illustrated ordescribed. A rotatable member 21 fits onto the motor shaft 20. beingvertically supported by the snap ring 22 or some other suitable means.The rotatable member 21 has an even numbered plurality of uniformlyspaced cutouts 21a around the periphery (FIG. 3). On each side of eachcutout is a guide slot 23 (FIGS. 2 and 3) to receive each tube rack. Thelower ends of the guide slot 23 are closed by the circular ring member24 which is secured to the rotatable member 21 by screws 25 or othersuit able means. The circular ring member 24 also acts as a stiffeningand restraining member resisting the outward thrust of centrifugal forceon the lower portions of the rotatable member 21.

Further referring to FIG. 2, there is shown a rack 11 of six tubes I0,rotated from the vertical position shown in FIG. 4 and inserted into therotatable member 21. The flanges 14 (FIG. 4) and the ends of the topplate I5 fit into the mating slots 23 (FIG. 2) of the retatable member.The rack is lowered into the rotatable member until it comes to restagainst the circular ring member 24.

The vertical height of the spacer guide 17 is made to cooperate with thecentral rotatable member 21 and the motor housing I9 so that. duringloading of a tube rack. if an individual tube is jostled radially inwarduntil the top stopper contacts the motor housing I9. part of the tube'slower stopper is still within its hole in the guide 17. Then when thecentrifuge motor starts to rotate. the displaced tube will be thrustradially outward by centrifugal force and will automatically repositionitself in the proper location.

After the tube racks I I (FIG. I I are positioned in the slots of therotatable member a cover 26 is placed on top of the rotatable memberclosing the upper ends of guide slots 23. Both the cover member 26 andthe rotatable member 2| are secured to the motor shaft 20 by screwingthe knurled and slotted knob 27 into the top of the shaft (FIG. 2).

The motor housing I9 (FIG. 2) rests on a base plate 28 from whichprojects upwardly a shell 29 which serves as a protective shroud aroundthe centrifuge.

When all eight tube racks with their 48 tubes are loaded into thecentrifuge as heretofore described and the cover 26 is secured with theknob 27, the centrifuge is spun at the speeds and time intervals dcsired(which may be automatically programmed) so that the different liquidsand/or solids are separated in all the tubes. Then the centrifuge isstopped and the racks of tubes are unloaded and placed in a tube rackcarrier 30 (FIG. 8) for transfer to the location where tests are to beperformed or the different elements are to be analyzed or handled.

The apparatus has great flexibility for centrifuging fewer tubes than afull load of 48 tubes. Any pairs of racks may be omitted as long as theempty regions are ones symmetrically across a diameter of thecentrifuge. so that dynamic balancing will be preserved. Also twoopposite racks having less than six tubes can be used as long as thesame number of tubes are in each and they are in the same respectivelocations in each rack to maintain dynamic balancing. If the number ofbloodfilled tubes on hand to be centrifuged is an uneven number. anadditional tube can be filled with water to provide a matching weightand this tube can be used with the others to provide an even number oftubes in total. for handling as described above. Thus. the apparatus andmethod of the present invention has complete flexibility in being ableto centrifuge any number of tubes at one time. from one up to a maximumof 48 tubes.

Referring to FIG. 8, the tube rack carrier 30 has a base 31, end members32 and a top 33. The top 33 has a plurality of cutouts 34 spaced fromeach other and each sized to receive a tube rack. Secured to the base 31are a pair of spaced. parallel guide members 35 which run the length ofthe base. Extending vertically from these members 35 are tabs 36 withbeveled corners. These tabs are located to guide the tube racks 1] intothe correct positions as they are inserted into cutouts 34 and loweredto the bottom of the carrier. When a tube rack is being lowered throughthe cutout 34 it can only be rocked right or left. If it comes to reston top ofa tab 36, the top of the tube rack will be so much higher thannormal and higher than other tube racks that it will be immediatelynoticeable and the operator will then shift it to its proper position.

The above description has covered the loading and unloading of thecentrifuge by the insertion or removal of the tube racks individually.In such case the rotatable member 2I has remained affixed to thecentrifuge. As an alternative. the entire rotatable member ZI loadedwith tube racks and tubes can be removed from the centrifuge andreplaced with another preload rotatable member. so that the second loadcan be centri fuged while the first load is being removed from the firstrotatable member and replaced with a third set of serum separators. Theremoval of the entire rotatable member and its load can be accomplishedby providing for the insertion of a pair of handles into the member bywhich the member can be lifted from the centrifuge. as shown in FIG. 9.The top of the rotatable member is provided with a pair of drilledtapped holes 37 (FIGS. 2 and 3), one on each side of the member. AT-shaped handle 38 (FIG. 9). having a threaded portion and a collar orboss 3811. which limits how far the handle can be screwed into the hole37 (FIG. 2 l. is used to lift the member 21 (FIGS. 2 and 9) on eachside. The knob 27 (FIG. 2) and the cover 26 are first removed. andhandles 38 FIG. 9) are screwed into the holes 37 (FIG. 2) and the entirerotatable member 2] (FIG. 9) with its load is removed from thecentrifuge. It is not necessary for the handles to be screwed so thatthe bosses 38a are tight against the rotatable member. It is onlynecessary for the handles to be screwed in sufficiently to prevent thehandles from becoming detached from the member. The handles can beoriented so that the cross members are approximately parallel. Onehandle can then be grasped in each hand with two fingers and the entirerotatable member lifted from the centrifuge and placed on an adjacentwork table for loading and reloading. After is has been reloaded it isreinstalled on the motor shaft by reversing the steps described above.

The centrifuge of the present invention has been described andillustrated in connection with serum/- plasma separator tubes used inthe separation of blood into its light and heavy phases. However. itwill be understood that the centrifuge can also be used for theseparation of other liquids into their various phases.

It will be obvious to those skilled in the art that variousmodifications may be made to the apparatus hereinbefore described. Suchembodiments are considered to be within the scope of the invention. Theabove in vention is not to be limited except as set forth in thefollowing claims.

Having thus described the invention, what is claimed I. A centrifuge forliquid separator tubes comprising: drive means. a rotatable membermounted on the drive means. said rotatable member having an evennumbered plu rality of uniformly spaced supports around the periphery ofthe rotatable member with opposite supports equidistant from the axis ofthe drive means. a rack adapted to hold a plurality of separator tubesspaced from each other. said rack having means to mount the rack in thesaid supports of the rotatable member in an attitude normal to the saidaxis. and means to secure the racks in the supports. said rackcomprising:

a. a pair of vertical side members spaced from each other by a distancegreater than the diameter of said separator tubes and having a heightless than the height of said separator tubes;

b. a base member connecting the said side members and adapted to supportthe separator tubes during loading, unloading and centrifugation;

c. a longitudinal guide member spaced from the base member and supportedby the side members and adapted to evenly space the bottoms of theseparator tubes; and

d. a top rack member having a series of holes larger than the separatortubes and adapted to space said tubes:

c. said top rack member being secured to bent over edge portions of saidvertical side members to form a pair of flanges adapted to fit intocooperating slots in the said supports of the rotatable member andretain the rack in the rotatable member.

2. The centrifuge of claim 1 in which the rotatable member is detachablymounted to the drive means whereby the said member loaded with racks oftubes can be removed from or loaded onto the centrifuge as a unit.

3. The centrifuge of claim 2 which includes handle means detachablysecured to the said rotatable member whereby the rotatable member andracks may be lifted in and out of the centrifuge as an assembly,

4. The centrifuge of claim 3 wherein the handle means comprise twohandles located along a diameter passing through the axis of saidrotatable means and each handle is located equidistant from said axis.

5. The centrifuge of claim 4 wherein the handle means includes a pair ofT-shapcd portions adapted for comfortable and efficient lifting by thetwo hands of a user.

6. The centrifuge of claim 5 wherein the T-shaped portion of each handlemeans is insertable into the rotatable member and includes a bossadapted to limit the distance the handle means can be inserted into therotatable member.

7. The centrifuge of claim 1 in which each support comprises a cutout inthe rotatable member parallel to the axis of the drive means to receivethe said rack and which includes safety closure means detachably mountedto close the upper ends of the said cutouts so that the racks aresecured in position while the rotatable member is spinning.

1. A centrifuge for liquid separator tubes comprising: drive means, arotatable member mounted on the drive means, said rotatable memberhaving an even numbered plurality of uniformly spaced supports aroundthe periphery of the rotatable member with opposite supports equidistantfrom the axis of the drive means, a rack adapted to hold a plurality ofseparator tubes spaced from each other, said rack having means to mountthe rack in the said supports of the rotatable member in an attitudenormal to the said axis, and means to secure the racks in the supports,said rack comprising: a. a pair of vertical side members spaced fromeach other by a distance greater than the diameter of said separatortubes and having a height less than the height of said separator tubes;b. a base member connecting the said side members and adapted to supportthe separator tubes during loading, unloading and centrifugation; c. alongitudinal guide member spaced from the base member and supported bythe side members and adapted to evenly space the bottoms of theseparator tubes; and d. a top rack member having a series of holeslarger than the separator tubes and adapted to space said tubes; e. saidtop rack member being secured to bent over edge portions of saidvertical side members to form a pair of flanges adapted to fit intocooperating slots in the said supports of the rotatable member andretain the rack in the rotatable member.
 2. The centrifuge of claim 1 inwhich the rotatable member is detachably mounted to the drive meanswhereby the said member loaded with racks of tubes can be removed fromor loaded onto the centrifuge as a unit.
 3. The centrifuge of claim 2which includes handle means detachably secured to the said rotatablemember whereby the rotatable member and racks may be lifted in and outof the centrifuge as an assembly.
 4. The centrifuge of claim 3 whereinthe handle means comprise two handles located along a diameter passingthrough the axis of said rotatable means and each handle is locatedequidistant from said axis.
 5. The centrifuge of claim 4 wherein thehandle means includes a pair of T-shaped portions adapted forcomfortable and efficient lifting by the two hands of a user.
 6. Thecentrifuge of claim 5 wherein the T-shaped portion of each handle meansis insertable into the rotatable member and includes a boss adapted tolimit the distance the handle means can be inserted into the rotatablemember.
 7. The centrifuge of claim 1 in which each support comprises acutout in the rotatable member parallel to the axis of the drive meansto receive the said rack, and which includes safety closure meansdetachably mounted to close the upper ends of the said cutouts so thatthe racks are secured in position while the rotatable member isspinning.